1. Technical Field
The present invention relates to a dual lock apparatus, and in particular, to a dual lock apparatus that has at least two independent means of acting on a lock whereby operation of the two locking means is controlled by an improved clutch mechanism.
2. Background Information
In a previous patent by the same applicant (PCT/AU01/00579 entitled ‘A Dual Lock Apparatus’), whose contents are expressly incorporated by reference herein, there was disclosed a locking apparatus having at least two independent means of acting on a lock. Although the apparatus as described in the aforementioned patent has been found to function satisfactorily, an improved clutch mechanism which allows the two locking mechanisms to function independently has been developed and is the subject of the present application.
There are numerous types of locks in existence today that are used to secure various devices. One of the more common uses of locks is in relation to doors. Typically door locks have a bolt that can be extended from a locking mechanism so as to engage a doorframe or furniture with the bolts being driven by the use of a unique or slave key. There have also been developed locks that are not only operable by the use of the slave key but also a master key, allowing the master key holder, for example, to operate all doors in a pre-defined area whilst the slave key holders are limited to being able to operate specific doors only. This however requires the master key and the slave key to be of the same type thus potentially compromising security.
There have also been developed electromechanical locks that use an electric motor to drive the bolt. The difficulty with these types of arrangements is that if the electric motor was for whatever reason inoperable, the door may be left either in the unlocked or locked state and may require disassembly to be fixed.
Further still, the difficulty with some existing locks is that although the door may be unlocked, that is it may be opened, the bolt still engages a portion of the door frame and further manual operation of the bolt by the use of a handle is required to be able to open the door. On the other hand, if the bolt was to be retracted fully, then the door may swing freely, also an undesirable effect.
It is an object of the present invention to propose a locking apparatus that overcomes at least some of the abovementioned problems or provides the public with a useful alternative.
Although the present specification discusses doors in particular it is to be understood that the present invention is not intended to be limited to doors and may equally well be used to provide a locking apparatus in relation to other devices such as safes and gates to name but two.